#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main(void)
{
	int arr[10] = { 0 };
	int i;
	float average = 0;
	int num = 0;
	for (i = 0; i < 10; i++)
	{
		scanf("%d", &arr[i]);
	}
	for (i = 0; i < 10; i++)
	{
		num += arr[i];
	}
	average = num / 10.0;
	printf("%f", average);
	return 0;
}